Those travelling to Heathrow by car could face a congestion charge should the west London airport be chosen for expansion.

Bosses at Heathrow will tell the Whitehall-appointed Airports Commission there could be a case for introducing a charge once improvements in public transport in the area are delivered.

Such a charge would not apply to surrounding roads such as the M25, the M4 and the A4, but would affect vehicles travelling to the airport.

Funds could be ring-fenced to contribute towards major rail, London Underground and road improvements, as well as pay for further sustainable travel initiatives, public transport schemes and community transport improvements, say Heathrow chiefs.

The airport's bosses also envisage an exemption to any charge for the greenest vehicles and for taxis and local residents.

The congestion charge is part of an overall revised submission by Heathrow's bosses to the Airports Commission in the battle to win the commission's approval for a third runway.

Led by former Financial Services Authority chief Sir Howard Davies, the commission has also shortlisted an extra runway at Gatwick for more consideration in its deliberation which also includes taking a further look at the so-called "Boris Island" option of a new airport in the Thames Estuary.

Sir Howard and his team will make their final recommendation in summer 2015 on where airport expansion should go ahead. Heathrow will be publishing its full revised submission next week.

Heathrow's head of s urface access Simon Earles said: "During our recent community consultation people raised concerns about the impact of a new runway on traffic congestion and air pollution.

"Once improvements to public transport to the airport have been delivered we believe there may be a case for a congestion charge for passengers travelling to the airport to reduce congestion, improve air quality, and raise money for further public transport improvements. The idea is at an early stage and we will of course consult on these plans at the appropriate time."

RAC Foundation director Professor Stephen Glaister said: "There's nothing new in charging access to a private site and this is a matter between Heathrow and its customers.

"Given the enormous growth potential at Heathrow, it seems right the owner does something to limit the impact of congestion and pollution on those living around the airport. Better still if the money is spent fixing potholes on local roads, as is one of the options temptingly being suggested."

The Thames Estuary airport option is favoured by London Mayor Boris Johnson, who is vehemently opposed to expansion at Heathrow.

Mr Johnson's aviation adviser D aniel Moylan said today: "It appears Heathrow may finally have woken up to the fact that the madness of building a third and then inevitably a fourth runway in west London would have a catastrophic effect on local roads not to mention their own site.

"If true that on top of pricey parking charges they are now considering some form of additional road-user charge it will be extremely unpopular with families heading for their well-earned breaks.

"Heathrow have always underestimated the impact of increasing runway capacity in an area where public transport already strains at the seams and my impression is that they do not give a fig for the wellbeing of west London."

Gatwick's chief executive Stewart Wingate said: "It was only a matter of time before this Heathrow bombshell was dropped.

"On the eve of final submissions to the Airports Commission, Heathrow have been forced to announce unprecedented measures to tackle one of the huge environmental challenges of their expansion plans."